Antibiotic Activity and Structural Analysis of a Scorpion-derived Antimicrobial peptide IsCT and Its Analogs

Experimental Data Snapshot

  • Method: SOLUTION NMR
  • Conformers Calculated: 50 
  • Conformers Submitted: 20 
  • Selection Criteria: structures with the lowest energy 

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Antibiotic activity and structural analysis of the scorpion-derived antimicrobial peptide IsCT and its analogs

Lee, K.Shin, S.Y.Kim, K.Lim, S.S.Hahm, K.S.Kim, Y.

(2004) Biochem Biophys Res Commun 323: 712-719

  • DOI: https://doi.org/10.1016/j.bbrc.2004.08.144
  • Primary Citation of Related Structures:  
    1T51, 1T52, 1T54, 1T55

  • PubMed Abstract: 

    IsCT is a non-cell-selective antimicrobial peptide isolated from the scorpion Opisthacanthus madagascariensis that has potent cytolytic activity against both mammalian and bacterial cells. To investigate the structure-activity relationships of IsCT and to design novel peptide antibiotics with bacterial cell selectivity, we synthesized several analogs of IsCT and determined their three-dimensional structures in solution by 2D-NMR spectroscopy. IsCT has a linear alpha-helical structure from Gly3 to Phe13, and [K7]-IsCT has a linear alpha-helical structure from Leu2 to Phe13. [K7, P8, K11]-IsCT, which has a bend in its middle region, exhibited the highest antibacterial activity without hemolytic activity, suggesting that its proline-induced bend is an important determinant of this selectivity. Tryptophan fluorescence showed that the high selectivity of [K7, P8, K11]-IsCT toward bacterial cells is closely correlated with its highly selective interaction with negatively charged phospholipids. Its potent activity against antibiotic-resistant bacteria suggests that [K7, P8, K11]-IsCT may serve as a promising lead candidate in the development of new peptide antibiotics.

  • Organizational Affiliation

    Department of Chemistry and Bio/Molecular Informatics Center, Konkuk University, Seoul 143-701, Republic of Korea.


Find similar proteins by:  Sequence   |   3D Structure  

Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Cytotoxic linear peptide IsCT14Opisthacanthus madagascariensisMutation(s): 1 
Find proteins for Q8MMJ7 (Opisthacanthus madagascariensis)
Explore Q8MMJ7 
Go to UniProtKB:  Q8MMJ7
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ8MMJ7
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: SOLUTION NMR
  • Conformers Calculated: 50 
  • Conformers Submitted: 20 
  • Selection Criteria: structures with the lowest energy 

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2004-10-19
    Type: Initial release
  • Version 1.1: 2008-04-30
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2021-11-10
    Changes: Data collection, Database references, Derived calculations